Hey guys I'm kinda new here so i don't know if this in the right thread or not. If not i i'm sorry but i have a quik question. I read in Bruce's exhaust and intake data on the website and decided too wake up my car a little bit. I did the exhaust a couple of weeks ago and installed a cold aire intake yesterday as well as removed the MAF screen.... But no difference!!!!! the only thing i can think of as to why is my exhaust, I bought one V-Force V12 muffler its 2.5 center inlet and dual 2.5 outlet . I put the muffler in the place of the Y pipe installed a performance cat and had tails bent and put on factory tips... is it possible that i lost too much backpressure by elimating a muffler? please help thanx.

danbuc

09-02-07, 02:29 PM

First things first.....pulling the MAF screen was a mistake. That probably cost you some power, now that the MAF sensor isn't getting accurate readings. The screen is NOT a restriction, and is there to straighten the airflow across the sensor to ensure proper readings. The "CAI" probably also hurt your low end a bit. ARe you just using a cone type filter sitting right under the engine compartment, or did you run something down into the fender well area?

fubar569

09-02-07, 02:36 PM

funny you should mention you didnt gain anything...

personally i dropped over .5 of a second by modding my airbox and completely gutting my stock exhaust. I then gained even more time by welding my own custom dual 2.5" catback for the car again with no mufflers...i recently added custom cut and repacked cherrybombs for resonance control (i dont feel any loss of power by adding 2 10" glasspacks)

the one thing i DID NOT DO was remove the MAF screen! that is a BIG NO NO!!

My timeslips prove consistent gains with my mods...all the way down to a 14.76 @ 9x mph...

AJxtcman

09-02-07, 03:35 PM

It really is an air straightener not a screen.
Your car should not have any or very little back pressure from the factory.

Ranger

09-02-07, 04:59 PM

It really is an air straightener not a screen.
AJ took the words out of my mouth.

eldorado1

09-02-07, 07:12 PM

"No difference" meaning what? Something you feel? Dyno #'s?

I think it takes about 30-50hp for your butt dyno to register a difference. If you did one, then the other, you might have gotten used to it already.

codewize

09-02-07, 10:56 PM

As mentioned, removing the MAF screen was definitely a mistake, please ask questions before doing stuff like that, you'll learn a lot around here.

Secondly what's the intake setup? If it's a conical filter off the intake you're probably going to loose HP by drawing hot air into the intake. so far no one has proven that a CAI of any kind produces gains, however I tried like hell and intend to prove one way or the other.

Next the exhaust, the ONLY restriction in the flow of air through a N* is the front to rear crossover, which has proven to be almost imposable to redesign. So unless you changed that you probably also decrease you HP by overly decreasing back pressure. Additionally it's been said that the larger exhaust could cool the exhaust gases faster making it more dense and more difficult to move.

All or some of these mods may gain you power in the very high RPM range but you'll loose torque like crazy from idle to 4000 RPM

The answer is to put the car on a dyno and prove one way or the other.

fubar569

09-02-07, 11:19 PM

As mentioned, removing the MAF screen was definitely a mistake, please ask questions before doing stuff like that, you'll learn a lot around here.

Secondly what's the intake setup? If it's a conical filter off the intake you're probably going to loose HP by drawing hot air into the intake. so far no one has proven that a CAI of any kind produces gains, however I tried like hell and intend to prove one way or the other.

Next the exhaust, the ONLY restriction in the flow of air through a N* is the front to rear crossover, which has proven to be almost imposable to redesign. So unless you changed that you probably also decrease you HP by overly decreasing back pressure. Additionally it's been said that the larger exhaust could cool the exhaust gases faster making it more dense and more difficult to move.

All or some of these mods may gain you power in the very high RPM range but you'll loose torque like crazy from idle to 4000 RPM

The answer is to put the car on a dyno and prove one way or the other.

thus being the case, how does one argue with timeslips and trap speeds?

codewize

09-02-07, 11:42 PM

Not arguing. These mods may or may not affect 1/4 mile ET's but on the street may feel like an HP loss. Sometimes that factory low end torque will far outweigh the hi RPM HP gains form these mods. It really does depend on the exact things changed and the year of the engine.

See this is the problem, n one really knows. Hitmoney also says he gained HP from the Corsa but he didn't have a baseline dyno to start with. This is why I wanted to lay down numbers stock, after the CAI and then again after the Corsa. This is being worked on as we speak.

If you're getting lower ET's from the exhaust then fine I believe you but is it based on HP gains? if so where is the gain in the RPM range? Unless you did those runs back to back on the same day then it's really useless information, right? It may be a result in something a subtle as air temp. Every 10 degree difference affects the HP by 1%

It's just such an ongoing discussion. I'm not saying any of this is fact I'm just saying this is what we hear. Which again, is why I'm trying to prove all of it one way or the other and I will and that will be the end of the discussion.

thus being the case, how does one argue with timeslips and trap speeds?

fubar569

09-03-07, 12:39 AM

It's just such an ongoing discussion. I'm not saying any of this is fact I'm just saying this is what we hear. Which again, is why I'm trying to prove all of it one way or the other and I will and that will be the end of the discussion.

very true...and i cant wait either :thumbsup:

jadcock

09-03-07, 08:27 AM

I'm curious about the exhaust setup. 1996Eldorado, you replaced TWO mufflers with ONE? Do I read that right? I think you may have hurt exhaust performance (added backpressure) by doing that. Can you get a picture of what your rear muffler setup looks like? You have a large, single, muffler sitting aft of the rear wheels, right...under the trunk...where the stock mufflers were? In order to have one muffler there, instead of two, I would think that the pipe routing might be a bit convoluted to keep the dual exhaust outlets. I realize this is what they had with the '92 Seville, but that was also with the 4.9L engine. Different exhaust volume/velocities there. I'm sure they moved to two mufflers on the Northstar cars for a reason.

I agree with the rest, regarding removing the MAF sensor straightener and possible low-end loss from the "cold air intake". Can you provide a picture of both the "cold air intake" and the exhaust? The reason I put "cold air intake" in quotation marks is I suspect that it's actually a "hot air intake", and may decrease your performance. The factory intake setup is about as "cold air" of an intake as you're going to get.

Looking forward to hearing back from you. We'll be able to get to the bottom of this!

96Fleetwood

09-03-07, 10:51 AM

On my Fleetwood, I did not see the full effect of my modifications until I took it to the dyno and got it professionally tuned. The car needs to be adjusted for the new air, fuel, ignition, etc values. Are there any tuners for the Northstar?

codewize

09-03-07, 11:24 AM

You don't count. We're talking about N* powered cars here. The L05 and LT1 cars are almost the opposite in the fact that they're pretty much infinitely mod-able.

I can change the spark plugs on them and gain 10HP LOL (JK)

On my Fleetwood, I did not see the full effect of my modifications until I took it to the dyno and got it professionally tuned. The car needs to be adjusted for the new air, fuel, ignition, etc values. Are there any tuners for the Northstar?

msta293412

09-06-07, 08:35 AM

Yea LT1 man, you're putting salt in our wounds. There is no "fine tuning" ffor northstars. Allthough AJ is close.....Just a foot note but, when I did my exhaust and intake etc., My car needed a day or 2 of getting on the gas pedal for the car to "learn" or get used to the mods....it actually got faster after a couple of days...